The present invention relates to a cutting insert for chipforming machining of metallic workpieces comprising at least one cutting corner and an adjacent cutting edge provided at the intersection between an upper rake face and a lower clearance face on the insert, the rake face being provided with a chip breaking recess. The invention also relates to a drilling tool equipped with such an insert.
Prior art drilling tools, including a drill shaft equipped with inserts having one or several sintered-in chip breaking grooves in the rake face are disclosed for instance in U.S. Pat. No. 4,215,957. Such drilling tools, however, cannot always provide a desirable optimum formation of the chip. It is often desirable to be able to obtain very short comma-shaped chips, thus making it possible to increase the efficiency of chip discharge. At the same time, however, a reduction of the energy needed for powering the drill has not been achievable.
It is, therefore, an object of this invention to provide a novel insert and a drilling tool that enables a more favorable chip formation when drilling occurs in tough materials and materials of medium tough conditions.
It is another purpose of the invention to provide a new type of insert and a drilling tool that enables a reduction of the power energy needed for its operation.